The Factory Fatty is reminiscent of the "works" or cone pipe once used by Factory Teams. It shares many of the same characteristics with its craftsmanship and material quality. Thoroughly tested and developed by the best racers in the sport, this pipe delivers true "works" style technology to the public. Looking to turn your bike into a race-ready powerhouse? The Factory Fatty is the first step you should take for bolt-on performance.

Works performance meets superior style.

Offers increased torque and throttle control.

Used by record breaking madman Robbie Maddison and the FMF Factory off-road team.

Supplied O-rings ensure a flawless fit.

Quality construction for maximum durability.

Unplated 20-gauge header and 19-gauge body for that "Factory" look.

The perfect modification to any 2-stroke race bike.

Note: Pipe may include factory indentations for proper installation clearance.

Note: For closed course competition use ONLY. Not intended for street use.

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14 Reviews

4.9 out of 5 stars

5 Star184 Star23 Star02 Star01 Star0

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Made a noticeable bottom end power increase, pleased with the performance and would recommend this product.

On the appearance side it could be better. The welds aren't very good and they never got touched up or finished so the welds are already rrusted. There was also a very minor dent but I am more concerned with performance not appearance. Overall good product.

Bought this for a good friends son. He rides almost all off road, hare scrambles, and enduros and even a GNCC. He was excited!! He said it was a total improvement over stock . Fit and finnish COOL! FMF makes quality stuff!

Installed on an 05 RM250 Race Bike that previously had the FMF Fatty and noticed an immediate improved in throttle response, and better top end. Not to mention the sound of the bike is much more crisp. Sounded and performed better than a PC on an identical 05RM250. Also purchased a PowerCore II Titanium silencer to complement the pipe. Bike dropped about three pounds over the old Fatty & Silencer. Be sure to cover pipe in Pam during rides. Post ride; clean then lubricate with WD40 as it is the works finish and will rust.

This pipe is so worth the money. 22% HP gain in this bike. 2.5hp and it hits hard. Turn your sr into an sxs with this pipe. They do not do anything different at the factory. Go from an 85 to a 90 main jet and let it rip. Evan is now getting the holeshots on the cobra's

love the pipe and its almost worth your money but if u put your bike away muddy or dirty the it will rust and it will not come off with wd40.it wont look the best if u dont wash it after your done riding.

I have this pipe on both my 05' CR125 and 07' CR250. For 125's you can expect a healthy increase in midrange pull with a little bit more over rev. Throttle response is also improved slightly if jetted correctly. For a 250 you can expect to see an increase in the bottom through midrange with a little more over rev. Where this pipe stands out is that it delivers a healthy amount of power just about everywhere but in a useable nature. Fit and bolt on is spot on and both pipes were matted with a shorty silencer. I gave the durability a 4 because as with any "works" finish pipe you have to rub it down with wd40 and give it a sos pad scrub once in a while to keep away the rust. Overall great pipe from a company keeping 2 strokes alive.

A: Fatty pipes are designed to give the engine an all around power increase. We are not drastically altering the power band of the bike. This pipe will appeal to most people that are happy with the stock power band and just looking for more useable power everywhere. You would probably want to go with the SST. Think of the SST as a mix between the Fatty, and the Rev pipe with a little help from the rear SST section. This pipe gives an all around power increase similar to the Fatty, yet gives it even more mid and top like the Rev without sacrificing low end. This pipe offers a new power band that wasn't available in the past, with its new technologies.

Chestersx

Location: Ga

Q: Ktm jetting?

1 year 5 months ago

What jetting setup could I run on a 2015 Ktm 250 sx at 1,000 -2500 elevation in 80-90 weather. Thanks

A: There is not a specific setting I could give you for jetting your bike. It would really depend on how your bike is running with the current jetting. Jetting can be very tricky, there isn't one setting that will work everywhere with every bike. I would recommend taking your bike to a local motorcycle dealership’s service department to have your bike properly jetted.

kyle

Q: Why wont it work on a yz 125 2004 i really like this pipe but dont understand why its not working.?

1 year 5 months ago

if I have a 04 and this pipe that i like wont fit should i order the 05 one or will it not fit?

A: Unfortunately FMF does not offer the FMF Factory Fatty Pipe for your 2004 Yamaha YZ125. In 2005 Yamaha switched from the steel frame to the aluminum frame on the YZ125. Because of that the 2005+ pipe will not mount on the 2004.

Bailey

Location: Queensland, Australia

Q: Does this pipe come the same shape and style like the photo if bought for. 2015 ktm 125 and will it fit onto a titanium 2 silencer and how more HP?

A: The image is a generic image supplied by the manufacturer for reference only. It may not be displaying the exact part for your bike. Just be sure to correctly select the Year/Make/Model of your bike before ordering so we can be sure to send you the correct pipe for your bike. Also, feel free to give us a call at 888-676-8853 and we would be happy to help you out with your order.

Jake

Q: My friend has this exact pipe on his 2007 Honda CR125, but when I select my 2005 Honda CR125 it says the pipe is not compatible, why is that?

1 year 7 months ago

This is the exact pipe on my friend's 2007 Honda CR125 and I've been wanting to put the same pipe on my 2005 Honda CR125, but it says this pipe will not work with my bike when it clearly will. Why is that?

A: Yes this FMF Factory Fatty Pipe will work with the FMF Turbinecore 2 on your 2008 KTM 105SX. Just be sure to correctly select the Year/Make/Model of your bike before ordering so we can be sure to send you the correct pipe for your bike. Also, feel free to give us a call at 888-676-8853 and we would be happy to help you out with your order.